A Study of EPX-100 (Clemizole Hydrochloride) in Participants With Dravet Syndrome (ARGUS)

May 12, 2026 updated by: Epygenix

A 20-Week Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial of EPX-100 (Clemizole Hydrochloride) as Adjunctive Therapy in Children and Adult Participants With Dravet Syndrome (ARGUS Trial)

This is a multicenter, Phase 3, randomized, double-blind, placebo-controlled study designed to evaluate the efficacy and safety of clemizole hydrochloride (EPX-100) as adjunctive therapy in children and adult participants with Dravet syndrome (DS).

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a global, multicenter, randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of clemizole hydrochloride as adjunctive therapy in children and adult participants with DS. The study consists of a 4-week Observational Period, a 16-week Double-Blind (DB) Period and an Open-Label Extension (OLE) Period.

Study Type

Interventional

Enrollment (Estimated)

150

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Canada
    • British Columbia
      • Vancouver, British Columbia, Canada, V6H 3V1
        • Recruiting
        • UBC Children's Hospital Research Institute
        • Principal Investigator:
          • Mary Connolly, MD
        • Contact:
        • Contact:
    • Ontario
      • Ottawa, Ontario, Canada, K1H 8L1
        • Recruiting
        • Children's Hospital of Eastern Ontario Research Institute Inc.
        • Contact:
        • Principal Investigator:
          • Katherine Muir, MD, FRCPC
        • Contact:
      • Toronto, Ontario, Canada, M5G 1X8
        • Recruiting
        • The Hospital for Sick Children
        • Contact:
        • Principal Investigator:
          • Elizabeth Donner, MD
      • Toronto, Ontario, Canada, M5T 2S8
  • Georgia
      • Tbilisi, Georgia, 0186
        • Recruiting
        • Institute of Neurology and Neuropsychology LTD
        • Principal Investigator:
          • David Kvernadze, MD
        • Contact:
      • Tbilisi, Georgia, 0159
        • Recruiting
        • Tbilisi State Medical University, Givi Zhvania Academic, Clinic of Pediatry
        • Principal Investigator:
          • Sophia Bakhtadze, MD
        • Contact:
      • Tbilisi, Georgia, 0160
        • Recruiting
        • Medi Club Georgia LLC
        • Principal Investigator:
          • Gia Melikishvili, MD
        • Contact:
  • Hungary
      • Budapest, Hungary, 1085
        • Recruiting
        • Semmelweis University
        • Principal Investigator:
          • Viktor Farkas, MD
        • Contact:
      • Debrecen, Hungary, 4032
        • Recruiting
        • University of Debrecen
        • Principal Investigator:
          • Mónika Bessenyei, MD
        • Contact:
  • India
      • Hyderabad, India, 500034
        • Not yet recruiting
        • Rainbow Children's Hospital
        • Contact:
        • Principal Investigator:
          • Lokesh Lingappa
      • Kochi, India, 682041
        • Not yet recruiting
        • Amrita Institute of Medical Sciences & Research Center
        • Contact:
        • Principal Investigator:
          • KP Vinayan
      • Mumbai, India, 400026
        • Not yet recruiting
        • Jaslok Hospital & Research Centre
        • Contact:
        • Principal Investigator:
          • Anita Hegde
      • Mumbai, India, 400034
        • Not yet recruiting
        • SRCC Children's Hospital by NH
        • Contact:
          • Ankita Pandey
          • Phone Number: '91 73574 53734
        • Principal Investigator:
          • Pradnya Gadgil
      • New Delhi, India
        • Not yet recruiting
        • All India Institute of Medical Sciences
        • Principal Investigator:
          • Sheffali Gulati
        • Contact:
    • Gujarat
      • Surat, Gujarat, India, 395002
        • Active, not recruiting
        • Saachi Children's Hospital
    • Karnatka
      • Adugodi, Karnatka, India, 560029
        • Not yet recruiting
        • National Institute of Mental Health and Neurosciences (NIMHANS)
        • Contact:
        • Principal Investigator:
          • Ajay Asranna
    • Maharashtra
      • Nagpur, Maharashtra, India, 44015
        • Active, not recruiting
        • Central India Cardiology Hospital and Research Institute
    • Tamil Nadu
      • Vellore, Tamil Nadu, India, 632004
        • Not yet recruiting
        • Christian Medical College
        • Contact:
        • Principal Investigator:
          • Maya Thomas
  • Poland
      • Gdansk, Poland
        • Recruiting
        • University Clinical Center in Gdansk, Division of Developmental Neurology
        • Principal Investigator:
          • Maria Mazuriewicz-Bełdzińska, MD
        • Contact:
      • Krakow, Poland, 30-363
        • Recruiting
        • Medical Centre Plejady
        • Contact:
        • Principal Investigator:
          • Marta Żołnowska, MD
      • Warsaw, Poland, 01-211
        • Recruiting
        • Institute of Mother and Child
        • Contact:
        • Principal Investigator:
          • Elżbieta Stawicka, MD
  • Romania
      • Bucharest, Romania, 041914
        • Not yet recruiting
        • "Prof. Dr. Al. Obregia" Psychiatry Clinical Hospital
        • Principal Investigator:
          • Dana Craiu, MD
  • Spain
      • Barcelona, Spain, 08025
        • Recruiting
        • Hospital de la Santa Creu i Sant Pau
        • Contact:
        • Principal Investigator:
          • Alba Sierra, MD
        • Contact:
    • Madrid Provincia
      • Madrid, Madrid Provincia, Spain, 28009
        • Recruiting
        • Hospital Infantil Universitario Niño Jesús
        • Principal Investigator:
          • Victor Soto, MD
        • Contact:
  • United Kingdom
      • Cardiff, United Kingdom, CF14 4XW
        • Recruiting
        • Cardiff And Vale University Health Board
        • Contact:
        • Principal Investigator:
          • Anurag Saxena, MD
      • London, United Kingdom, WC1N 1EH
        • Recruiting
        • Great Ormond Street Hospital for Children
        • Principal Investigator:
          • Helen Cross
        • Contact:
      • Sheffield, United Kingdom, S102TH
        • Recruiting
        • Sheffield Children's Hospital
        • Principal Investigator:
          • Archana Desurkar, MD
        • Contact:
  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35233
        • Active, not recruiting
        • University of Alabama at Birmingham
    • Arkansas
      • Little Rock, Arkansas, United States, 72202
        • Active, not recruiting
        • Arkansas Children's Hospital
    • California
      • Los Angeles, California, United States, 90027
        • Terminated
        • Children's Hospital of Los Angeles
      • Orange, California, United States, 92868
        • Recruiting
        • University of California Irvine
        • Principal Investigator:
          • David King-Stephens, MD
        • Contact:
        • Contact:
      • San Francisco, California, United States, 94158
        • Recruiting
        • UCSF Medical Center
        • Principal Investigator:
          • Ernesto Gonzalez-Giraldo, MD
        • Contact:
    • Connecticut
      • New Haven, Connecticut, United States, 06510
        • Not yet recruiting
        • Yale University School Of Medicine
        • Contact:
        • Principal Investigator:
          • Aline Herlopian, MD
    • Delaware
      • Wilmington, Delaware, United States, 19803
        • Terminated
        • The Nemours Foundation
    • Florida
    • Georgia
      • Atlanta, Georgia, United States, 30328
        • Withdrawn
        • Clinical Integrative Research Center of Atlanta (CIRCA)
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Terminated
        • Ann & Robert H. Lurie Children's Hospital of Chicago
    • Kentucky
    • Michigan
      • Ann Arbor, Michigan, United States, 48109
        • Terminated
        • University of Michigan- Mott Children's Hospital
    • Nebraska
      • Omaha, Nebraska, United States, 68114
        • Recruiting
        • Children's Nebraska
        • Contact:
        • Principal Investigator:
          • Sookyong Koh, MD, PhD
        • Contact:
          • Malayna Unkel
          • Phone Number: 402-559-0686
    • New Jersey
      • Hackensack, New Jersey, United States, 07601
        • Terminated
        • Northeast Regional Epilepsy Group
      • Marlboro, New Jersey, United States, 07746
        • Active, not recruiting
        • Neurology Center for Epilepsy and Seizures
    • New York
      • New York, New York, United States, 10021
        • Recruiting
        • Weill Cornell Medical Center
        • Principal Investigator:
          • Zachary Grinspan, MD, MS
        • Contact:
      • New York, New York, United States, 10075
        • Not yet recruiting
        • Northwell Health - Lenox Hill Hospital
        • Contact:
        • Principal Investigator:
          • Ruben Kuzniecky, MD
    • North Carolina
      • Durham, North Carolina, United States, 27710
        • Recruiting
        • Duke University Health System
        • Principal Investigator:
          • Muhammad Zafar, MD
        • Contact:
      • Morrisville, North Carolina, United States, 27560
        • Active, not recruiting
        • Science 37
      • Winston-Salem, North Carolina, United States, 27157
        • Recruiting
        • Wake Forest Baptist Medical Center
        • Principal Investigator:
          • Gautam S Popli, MD, MBA
        • Contact:
    • Ohio
      • Cincinnati, Ohio, United States, 45229
        • Recruiting
        • Cincinnati Children's Hospital Medical Center
        • Contact:
        • Principal Investigator:
          • Gewalin Aungaroon, MD
        • Contact:
      • Cleveland, Ohio, United States, 44195
        • Recruiting
        • Cleveland Clinic
        • Principal Investigator:
          • Elia Pestana Knight, MD
        • Contact:
      • Columbus, Ohio, United States, 43205
        • Withdrawn
        • Nationwide Children's Hospital
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Recruiting
        • The Children's Hospital of Philadelphia
        • Principal Investigator:
          • Eric Marsh, MD, PhD
        • Contact:
    • Tennessee
      • Memphis, Tennessee, United States, 38103
        • Terminated
        • Le Bonheur Children's Hospital
    • Texas
      • Austin, Texas, United States, 78757
      • Dallas, Texas, United States, 75207
        • Withdrawn
        • UT Southwestern/Children's Health
    • Utah
      • Salt Lake City, Utah, United States, 84112
    • Washington
    • Wisconsin
      • Milwaukee, Wisconsin, United States, 53266
        • Not yet recruiting
        • Medical College of Wisconsin, Children's Wisconsin
        • Contact:
        • Principal Investigator:
          • Avantika Singh

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

2 years and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  1. Male and female participants 2 years and older at time of consent.
  2. Participant or parent/legally authorized representative (LAR) willing and able to provide written informed consent, assent (if applicable) prior to initiation of any study related procedures.

  3. Clinical diagnosis of DS. Participants must have seizures which are not completely controlled by AEDs with the following criteria:

    • Onset of seizures prior to 18 months of age,
    • Normal development at onset,
    • History of at least one type of countable motor seizure (CMS),
    • Brain MRI without cortical malformation (not including mild atrophy associated with the natural progression of DS),
    • Genetic mutation of the SCN1A gene must be documented.

Key Exclusion Criteria:

  1. Known sensitivity, allergy, or previous exposure to clemizole HCl.
  2. Exposure to any investigational drug or device <90 days prior to screening or plans to participate in another drug or device trial at any time during the study.
  3. Seizures secondary to illicit drug (this includes concomitant use of tetrahydrocannabinol [THC] and nonprescription cannabidiol preparations) or alcohol use, infection, neoplasm, demyelinating disease, degenerative neurological disease, or central nervous system disease deemed progressive, metabolic illness, or progressive degenerative disease.
  4. Concurrent use of lorcaserin. Note: Prior use of lorcaserin is permitted if at least 30 days have passed since the last dose.
  5. Concurrent use of fenfluramine.
  6. Epilepsy surgery planned during the study or epilepsy surgery within 6 months prior to Screening.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Participants will receive their first dose of study drug following randomization.
Drug: Placebo
Placebo will be administered as an oral solution.
Experimental: Double-blind clemizole HCl
Participants will receive their first dose of study drug following randomization.
Drug: Clemizole HCl
Clemizole HCl will be administered as an oral solution.
Other Names:
  • EPX-100
Experimental: Open-label clemizole HCl
Eligible participants who complete the DB Period will have the option to continue in the OLE Period, during which they will receive clemizole HCL for up to 3 years.
Drug: Placebo
Placebo will be administered as an oral solution.
Drug: Clemizole HCl
Clemizole HCl will be administered as an oral solution.
Other Names:
  • EPX-100

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percent Change in Countable Motor Seizures Per 28 Days (CMS-28) in the Titration Plus Maintenance Periods Relative to Baseline
Time Frame: From Baseline Period (Day 1) up to 16 weeks
Percent change in CMS-28 from the Baseline Period through the end of the DB period.
From Baseline Period (Day 1) up to 16 weeks
European Union: Percent Change in Countable Motor Seizures Per 28 Days in the Maintenance Period Relative to Baseline
Time Frame: From maintenance period Baseline (Day 29) up to Day 85
Percent change in CMS-28 from the Baseline Period through the end of the maintenance period.
From maintenance period Baseline (Day 29) up to Day 85

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of Participants with >=50% reduction in Countable Motor Seizures Per 28 Days in the Titration Plus Maintenance Periods Relative to Baseline
Time Frame: From Baseline Period (Day 1) up to 16 weeks
Proportion of participants with >=50% reduction in CMS-28 from the Baseline Period through the end of the DB Period.
From Baseline Period (Day 1) up to 16 weeks
European Union: Proportion of Participants with >=50% reduction in Countable Motor Seizures Per 28 Days in the Maintenance Period Relative to Baseline
Time Frame: From maintenance period Baseline (Day 29) up to Day 85
Proportion of participants with >=50% reduction in CMS-28 from the Baseline Period through the end of the maintenance period.
From maintenance period Baseline (Day 29) up to Day 85
Number of Countable Motor Seizure-free Days in the Titration Plus Maintenance Periods Relative to Baseline
Time Frame: From Baseline Period (Day 1) up to 16 weeks
Number of countable motor seizure-free days from the Baseline Period through the end of the DB Period.
From Baseline Period (Day 1) up to 16 weeks
European Union: Number of Countable Motor Seizure-free Days in the Maintenance Period Relative to Baseline
Time Frame: From maintenance period Baseline (Day 29) up to Day 85
Number of countable motor seizure-free days from the Baseline Period through the end of the maintenance period.
From maintenance period Baseline (Day 29) up to Day 85
Clinical Global Impression of Improvement - Clinician (CGII-C) Score
Time Frame: Day 85
CGII-C score at the end of the maintenance Period. This 1-item scale asks the clinician to rate how the participant's symptoms have improved or worsened relative to baseline.
Day 85
Clinical Global Impression of Improvement - Participant/Caregiver (CGII-P) Score
Time Frame: Day 85
CGII-C score at the end of the maintenance Period. This 1-item scale asks the clinician to rate how the participant's symptoms have improved or worsened relative to baseline.
Day 85
Percent Change in All Seizures in the Titration Plus Maintenance Periods Relative to Baseline
Time Frame: From Baseline Period (Day 1) up to 16 weeks
Percent change in all seizures at the end of the DB Period.
From Baseline Period (Day 1) up to 16 weeks
Percent Change in All Seizures in the Maintenance Period Relative to Baseline
Time Frame: From maintenance period Baseline (Day 29) up to Day 85
Percent change in all seizures at the end of the maintenance period.
From maintenance period Baseline (Day 29) up to Day 85
Incidence of Rescue Anti-epileptic Drug (AED) Use in the Titration Plus Maintenance Periods Relative to Baseline
Time Frame: From Baseline Period (Day 1) up to 16 weeks
Incidence of rescue AED use as measured by the number of days on rescue AEDs from the Baseline Period through the end of the DB Period.
From Baseline Period (Day 1) up to 16 weeks
Incidence of Rescue Anti-epileptic Drug Use in the Maintenance Period Relative to Baseline
Time Frame: From maintenance period Baseline (Day 29) up to Day 85
Incidence of rescue AED use as measured by the number of days on rescue AEDs from the Baseline Period through the end of the maintenance period.
From maintenance period Baseline (Day 29) up to Day 85
United States FDA: Proportion of Participants with >=50% Reduction in the Countable Motor Seizures Per 28 Days in the Maintenance Period Relative to Baseline
Time Frame: From maintenance period Baseline (Day 29) up to Day 85
Proportion of participants with ≥50% reduction in CMS-28 from the Baseline Period through the end of the DB Maintenance Phase only.
From maintenance period Baseline (Day 29) up to Day 85
Incidence of Treatment-Emergent Adverse Events (TEAEs)
Time Frame: From the first dose administration of study drug up to end of the study, approximately up to 172 weeks
Incidence of TEAEs will be compared among the treatment groups.
From the first dose administration of study drug up to end of the study, approximately up to 172 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Epygenix

Collaborators

Harmony Biosciences Management, Inc.

Investigators

  • Study Director: Amit Ray, MD, Harmony Biosciences Management, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 15, 2020

Primary Completion (Estimated)

April 1, 2027

Study Completion (Estimated)

May 1, 2029

Study Registration Dates

First Submitted

July 6, 2020

First Submitted That Met QC Criteria

July 6, 2020

First Posted (Actual)

July 8, 2020

Study Record Updates

Last Update Posted (Actual)

May 14, 2026

Last Update Submitted That Met QC Criteria

May 12, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • EPX-100-001
  • 2024-518628-57-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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